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rescaler: add some SSE2 code

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The rounding and arithmetic is not the same as previously, to prevent overflow cases for large upscale factors.

We still rely on 32b x 32b -> 64b multiplies. Raised the fixed-point precision to 32b
so that we have some nice shifts from epi64 to epi32.
Changed rescaler_t type to 'uint32_t' in order to squeeze in all the precision required.

The MIPS code has been disabled because it's now out-of-sync. Will be fixed in
a subsequent CL when the dust settles.
~30-35% faster

Change-Id: I32e4ddc00933f1b1aa3463403086199fd5dad07b
This commit is contained in:
Pascal Massimino
2015-09-25 14:34:02 +02:00
parent 1df1d0eedb
commit 76a7dc39e5
10 changed files with 320 additions and 44 deletions
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43
src/dsp/rescaler.c
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@ -100,18 +100,24 @@ void WebPRescalerExportRowExpandC(WebPRescaler* const wrk) {
assert(!WebPRescalerOutputDone(wrk));
assert(wrk->y_accum <= 0);
assert(wrk->y_expand);
assert(wrk->y_sub != 0);
if (wrk->y_accum == 0) {
for (x_out = 0; x_out < x_out_max; ++x_out) {
const int v = (int)MULT_FIX(frow[x_out], wrk->fy_scale);
dst[x_out] = (!(v & ~0xff)) ? v : (v < 0) ? 0 : 255;
const uint32_t J = frow[x_out];
const int v = (int)MULT_FIX(J, wrk->fy_scale);
assert(v >= 0 && v <= 255);
dst[x_out] = v;
}
} else {
const int64_t A = wrk->y_sub + wrk->y_accum;
const int64_t B = -wrk->y_accum;
const uint32_t B = WEBP_RESCALER_FRAC(-wrk->y_accum, wrk->y_sub);
const uint32_t A = WEBP_RESCALER_ONE - B;
for (x_out = 0; x_out < x_out_max; ++x_out) {
const int64_t I = A * frow[x_out] + B * irow[x_out];
const int v = (int)MULT_FIX(I, wrk->fxy_scale);
dst[x_out] = (!(v & ~0xff)) ? v : (v < 0) ? 0 : 255;
const uint64_t I = (uint64_t)A * frow[x_out]
+ (uint64_t)B * irow[x_out];
const uint32_t J = (uint32_t)((I + ROUNDER) >> WEBP_RESCALER_RFIX);
const int v = (int)MULT_FIX(J, wrk->fy_scale);
assert(v >= 0 && v <= 255);
dst[x_out] = v;
}
}
}
@ -122,21 +128,28 @@ void WebPRescalerExportRowShrinkC(WebPRescaler* const wrk) {
rescaler_t* const irow = wrk->irow;
const int x_out_max = wrk->dst_width * wrk->num_channels;
const rescaler_t* const frow = wrk->frow;
const int yscale = wrk->fy_scale * (-wrk->y_accum);
const uint32_t yscale = wrk->fy_scale * (-wrk->y_accum);
assert(!WebPRescalerOutputDone(wrk));
assert(wrk->y_accum <= 0);
assert(!wrk->y_expand);
if (yscale) {
for (x_out = 0; x_out < x_out_max; ++x_out) {
const int frac = (int)MULT_FIX(frow[x_out], yscale);
const uint32_t frac = (uint32_t)MULT_FIX(frow[x_out], yscale);
const int v = (int)MULT_FIX(irow[x_out] - frac, wrk->fxy_scale);
dst[x_out] = (!(v & ~0xff)) ? v : (v < 0) ? 0 : 255;
assert(v >= 0 && v <= 255);
dst[x_out] = v;
irow[x_out] = frac; // new fractional start
}
} else {
} else if (wrk->fxy_scale) {
for (x_out = 0; x_out < x_out_max; ++x_out) {
const int v = (int)MULT_FIX(irow[x_out], wrk->fxy_scale);
dst[x_out] = (!(v & ~0xff)) ? v : (v < 0) ? 0 : 255;
assert(v >= 0 && v <= 255);
dst[x_out] = v;
irow[x_out] = 0;
}
} else { // very special case for src = dst = 1x1
for (x_out = 0; x_out < x_out_max; ++x_out) {
dst[x_out] = irow[x_out];
irow[x_out] = 0;
}
}
@ -179,6 +192,7 @@ WebPRescalerImportRowFunc WebPRescalerImportRowShrink;
WebPRescalerExportRowFunc WebPRescalerExportRowExpand;
WebPRescalerExportRowFunc WebPRescalerExportRowShrink;
extern void WebPRescalerDspInitSSE2(void);
extern void WebPRescalerDspInitMIPS32(void);
extern void WebPRescalerDspInitMIPSdspR2(void);
@ -194,6 +208,11 @@ WEBP_TSAN_IGNORE_FUNCTION void WebPRescalerDspInit(void) {
WebPRescalerExportRowShrink = WebPRescalerExportRowShrinkC;
if (VP8GetCPUInfo != NULL) {
#if defined(WEBP_USE_SSE2)
if (VP8GetCPUInfo(kSSE2)) {
WebPRescalerDspInitSSE2();
}
#endif
#if defined(WEBP_USE_MIPS32)
if (VP8GetCPUInfo(kMIPS32)) {
WebPRescalerDspInitMIPS32();